public ActionResult Delete(string id)
        {
            string urlRequest     = Request.Path;
            string correctPattern = @"^/api/Flights/[a-zA-Z]{2}[0-9]{5}[a-zA-Z]{3}$";

            if (!Regex.IsMatch(urlRequest, correctPattern))
            {
                return(BadRequest());
            }
            bool succeed = flightManager.DeleteFlightById(id);

            if (succeed)
            {
                return(Ok());
            }
            return(NotFound());
        }